Weakening parts:
Yes, that works. Damage is cumulative (but not DISPLAYED in damage tab). waekening wings with MG works, but given the power of well aimed cannon rounds in convergence, i dont think it neccessary to do it.
Side note: damages wings even rip off faster under stress.
Yes, AH guns model reduced damage for distance. Im not sure if they take into account velocity - kinetic E as well, but they DO model dispersion (which is a LOT more spread out at distance).
Reynolds: Noone says shooting at d1000 is impossible. Its just a lot lower% then at d100.....